Apparatus for controlling tightness of fasteners



July 20, 1955 R. H. ALEXANDER I 3,195,702

APPARATUS FOR CONTROLLING TIGHTNESS OF FASTENERS Filed NOV. 16, 1960 3Shegts-Sheet l July 20, 1965 R. HQ ALEXANDER APPARATUS FOR CONTROLLINGTIGHTNESS OF FASTENERS July 20, 1965 R. H. ALEXANDER APPARATUS FORCONTROLLING TIGHTNESS OF FASTENERS Filed Nov. 16, 1960 3 Sheets-Sheet 5IN VEN TOR. ROBERT H. ALEXANDER I ATTORNEYS zez 3 United States Patent M3,195,132 APPARATUS FOR CQNTRGLLENG TEGHTNESS 0F FASTENERS Robert H.Alexander, Miarnishurg, (lhio, assignor, by

mesne assignments, to Rockwell P/lauufacturing Company, Pittsburgh, Pa,a corporation of Pennsylvania Filed Nov. 16, well, Ser. No. 69,756 14Qlaims. (Cl. 192-.tl%)

The present invention relates to an apparatus for controlling thetightening of fasteners, particularly threaded fasteners such as nuts,bolts, certain types of screws, and the like.

Experiments in the field of control tensioning of fasteners have shownthat in many instances there is less variation between the tension inlike fasteners if a constant or relative uniformly controlled energy isused for tightening like fasteners. The precise reasons for this havenot been determined, however experiments have shown this to be a fact.The present invention provides such a constant energy source for use intightening fasteners to provide a substantially uniform tension in likefasteners, and this invention also provides a method whereby likefasteners may be tightened to produce substantially uniform tensionstherein.

Accordingly, the primary object of this invention is to provided a novelapparatus for tightening fasteners, in

which a substantially constant tension is induced in such fasteners bycontrolling the amount of energy imparted thereto in tightening.

Another object of the invention is to provide a rotary impacting toolwhich may be regulated to strike a predetermined number of blowsautomatically and then to stop, requiring resetting by the operatorbefore further impacts can be delivered.

Another object of this invention is to provide a novel rotary impacttool in which the lapse of time of operation of the tool following thefirst impact blow delivered thereby can be adjusted, followed byautomatic shut oii of the tool to prevent further impacting.

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

In the drawings:

FIG. 1 is a view of a rotary impacting tool constructed in accordancewith the invention, with the drive mechanism and a portion of thecontrol therefor broken away and shown in vertical section;

FIG. 2 is a view similar to FIG. 1 with the parts in relatively movedposition;

FIG. 3 is a vertical section taken through the rear of the apparatus,and particularly through the rotary pneumatic motor and the controlvalves therefor;

FIG. 4 is a sectional view of the control valves taken on line 4-4 ofFIG. 3;

PEG. 5 is a vertical section on an enlarged scale through the handle andadjacent portions of the tool body, show ing the controls for the toolin accordance with the invention;

FIG. 6 is a view similar to PEG. 5, showing the parts in a movedposition;

FIGS. 7 and 8 are sectional views on a somewhat reduced scale showingfurther positions of portions of the controls shown in FIG. 5;

FIG. 9 is a sectional view of a portion of the controls shown in FIGS. 5and 6, with the parts in a further moved position;

FIG. 10 is a sectional view on a reduced scale, taken on line 1i1ll ofFIG. 5;

HG. 11 is a sectional view similar to FIG. 5, of a modified form of theinvention; and

dddEflhZ Patented July 2%, 1965 FIG. 12 is a somewhat schematic View ofa further modification of the invention, showing an electricalequivalent of the pneumatic apparatus shown particularly in FIGS. 1-8.

Referring to the drawings, which illustrate preferred embodiments of theinvention, a preferred form of the tool is a pneumatic impact wrench ofthe rotary type, adapted to operate from a suitable source of compressedair, and as shown in FIGS. 110, having a main body or casing 10 anddepending handle 12 which the operator may grasp to hold and manipulatethe apparatus. Adjacent the juncture of the handle with the body thereis a trigger 15 slidably mounted in the handle and positioned formanipulation by a finger of the operator. The nose portion of the bodyTill, shown particularly in FIGS. 1 and 2, carries a bushing 17 withinwhich there is mounted a rotary anvil 18 including an output connector19 of irregular cross-section adapted to be coupled to a suitabledriving tool such as a socket, bit, or the like. The portion of anvil 18located within housing it), and of larger diameter, includes a pluralityof lugs it? which project rearwardly thereof and form abutments forreceiving blows from a hammer 22 which in turn is provided withcomplementary striking lugs or surfaces 23.

The hammer is rotated, in either direction as selected, by a rotaryspindle 24 having a driving head 25 in which are formed a plurality ofgrooves 2s receiving balls 28. These balls in turn are seated withincomplementary grooves 29 in the hammer, and the grooves 25 and 29 areformed of generally V-shape, along the axis of rotation, such that ifthe hammer 22 is held stationary continued rotation of the spindle ineither direction will produce a withdrawing axial movement of hammer 22against the bias of spring 38. Further details and a complete eX-planation of such a system are found in United States Patent No.2,166,150, issued May 30, 1939.

The spring 39 seats upon a stationary ring 31 which is carried by aretainer bushing 32, which in turn rests against the enlarged portion 34of the spindle. This portion forms the cage element of a planetarygearing system which may be incorporated in the tool, and this cage inturn carries a plurality of planet gears, one of which is shown at 35mounted upon bearings 36 through which extends planet shaft 37, andthese shafts are in turn held in place by engagement with the bushing 32and against a portion of the rear supporting ball bearing 38 whichcarries the rearward end of the driving spindle. The planet gears meshwith a stationary internal gear 4t) which is suitably held in stationaryposition within the housing it), and these gears are driven by a pinion4-2 formed on a drive shaft of a reversible rotary pneumatic motorindicated by the general reference numeral 47 (FIG. 3

This motor includes a cylinder or barrel 48 mounted within the rear ofthe casing It and a rotor 50 which is located eccentrically within thebarrel 48 and attached to drive the shaft 45. A plurality of blades 52are carried by rotor 50, axially slidable therein, and engage with thewalls of the barrel 48 as shown. The barrel also cooperates with casingit) to form the chambers within which a pressure fluid, such ascompressed air, is introduced through the inlet chamber 54 and passage55 to produce rotation of rotor Si by reaction against the blades 52. Anexhaust port 56 is provided at the opposite sides of the motor, openinginto an exhaust chamber 57 (FIG. 1), and which may lead to suitablemuffler constructions (not shown) to muffie any obiectionable sound ofthe air under pressure exhausting from the tool.

At the base of the handle 12 there is a connector or internally threadedplug all for coupling to a source of pressure fluid for driving motor47. A suitable source, for example, might be a flexible hose connectedto a high pressure air system operating, for example, at around 90 psi.The upper end of the plug member 60 is formed with an internal chamber62, and a ball control valve 65 is located within this chamber, normallybiased to close against a seat '66 by .a spring 67. This spring is heldwithin the chamber by a retainer ring 68 threaded into the plug member60. At the lower end of. chamber 62, around the spring 67, there are anumber of radially extending passages 69 which open into into an annulargroove or passage 70 about the side of the plug member 69, and when thismember is seated properly in place the passage 70 communicates with acontrol passage 72 leading upwardly through the handle to a short crosspassage 73 which in turn opens into a cavity 74 for receiving thehousing '75 of the trigger 15 and the servo ball valve 77 which iscontrolled by the trigger. r

The housing 7-5 includes a :rear chamber 89 into which the ball 77 isreceived, and which communicates with the cross passage 73, and a seat82 against which the ball 77 is normally urged by the pressure of air inpassage 72. Thus, pressure fluid is normally cut off from the forwardcontrol chamber 85 in housing 75, and within this chamber there is anextension or control rod 86 of reduced diameter projecting from the rearof trigger 15 and surrounded by a spring 87 which normally biases thetrigger forward into the position shown in FIG. 5, such that therod-like portion 86 will not interfere with seating of ball 77. Movementof the trigger is limited by a pin 88 mounted crosswise in housing 75and extending partially into a crossed slot 89 formed in the trigger 15.Thus, when the trigger is depressed by an operator, ball 77 will beunseated to admit pressure air to chamber 35 and this air then flowsoutwardly throughthe outlet passage 90 to initiate opera 'tion of thetool.

Referring particularly to FIGS, 3, 4, 5, 6 and 9, immediately above theseat 66 in the plug body 60 there are a number of cross passages 92extending from a central cavity 93 on the opposite side of seat 66 fromball 65, and opening into an annular passage 94. This passage in turnopens into a motor air supply passage 95, portions of which are shown inFIGS. and 6, and the upper portion of which is shown in FIGS. 3, 4 and10. passage terminates at its upper end in the bore 97 in body whichextends'lengthwise of the body adjacent to the juncture of the handle 12therewith. The directional control valve 100 is rotatably received in asleeve 1&1 within the bore 97, and is suitably slotted on oppositesides, as shown generally at 102 such that air may be directedselectively to either the motor air supply line 55, for forwardrotation, or to the reverse rotation supply passage 55a, and the 0p--posite supply passage connected to exhaust to prevent a recompressionresistance from air carried by the blades past theexhaust port 56.Details of such a reversing valve are 'well known in the art, and therotation of the plug valve 100 to produce such selective direction ofthe pressure air supply is under the control of a conventional knob 193extending outwardly beyond the portion of the housing which contains thevalve.

Accordingly, opening of valve 77 by depression of trigger will notdirectly supply pressure air to motor 47 but will serve only to initiateopening of valve 65, as will presently be described, to provide forpassage of motive pressure fluid into chamber 95 and thus to thedirectional control valve 100 for driving the motor in the desireddirection. As noted, valve 65 is normally biased closed by spring 67. Onthe opposite side of the ball valve 65 there is a control pin 105 havingan enlarged head 106 received within chamber 93 and adapted to engageball 65. This pin is slidably mounted within an extension 108 of theplug body 60, and about this timed operation of the impacting tool.

extension there is a cutoff control piston 116 which is freely slidableabout the extension 198 and within a counterbore 112 formed in the endof a control mechanism housing 114. This housing is received instationary relation within the bore 115 which projects upwardly throughthe handle toward the trigger mechanism, and into which is threaded theplug body 61) at the lower end of the handle.

The housing 114 includes an upper chamber 119 in which is mounted aservo piston 120, and this chamber opens into the servo outlet passage94 from the trigger. Piston 120 is normally biased upward, toward thetop of chamber 119, by a spring 122, and the piston includes a rodportion 123 extending slidably through a bore 124 in the housing, andterminating in a carrier 125 which is of generally inverted U-shape, theforward arm thereof being broken away in FIGS. 5, 6 and 9, while theother "arm is shown in elevation. This carrier provides a mountcontrol.pin 105, as shown particularly in FIG. 5. Be-

neath the carrier and the pawls, surrounding the extension 108 andslidably mounted thereon, is the main cutoff control piston 1 10, andthis piston is suitable sealed to both the extension-108 and thecounterbore 112 within which it slides as shown. A main positioning andcontrol spring 133 surrounds the carrier and the pawls, and seats at oneend upon piston 110 and at its other end against the housing 114.

The piston 110 is provided with an annular control cam surface 149 whichis adapted to engage within the cam surfaces 135 on the pawls, and whenforced between the pawls to separate their lower ends against the forceof spring 132, to open or separate the lugs 136 and permit control pinto pass therebetween, as shown particularly in FIG. 9. The power for somoving the control piston 110 is provided by selectively supplying airunder pressure to chamber 142 beneath this piston, and above plug body69, through a control passage 145, portions of which are seen in FIGS,5, 6, 9 and 10.

Accordingly, when the trigger 15 is depressed and servo ball valve 77unseated thereby, air under pressure enters through passages 72 and 73,and through chamber 80 past the servo valve into the servo outletpassage 9t). This pressure air acts upon ser-vo piston 120 to depress itagainst spring 122, and carrier 125 likewise moves downwardly carryingpawls 130 into engagement with the control pin 105, and since spring 132is active to bring the actuating lugs 136 toward each other, theselugsengage the pin and depress and open the main air supply ball valve65. Motive fluid is thus supplied through passages 92 and 95 to thedirectional selective valve 160, and thence to motor 47.

The motor will drive the spindle 24 in the selected direction, and thisspindle in turn, through the ball and V-groove connection 26, 28, 29,will rotate hammer 22. Once the fastener being operated upon otterssufiicient resistance to rotation of anvil 18, the anvil will be stoppedand the ball and V-groove mechanism will cause hammer 22 to retractagainst spring 36 until the lugs 23 and 20 disengage, whereupon thehammer will accelerate forward in both a rotary and axial direction toreengage the lugs 30 a d 23,, Striking a blow on the anvil 18.

At the first such retraction of the hammer 22, to initiate the impactingoperation, a signal is provided to commence operation of the controlpiston 110, thus beginning the In the embodiment shown in FIGS. 1, 4, 5,7 and 8, the mechanism are provided for this purpose includes a followersiidably mounted within a housing 152 which in turn is press fitted in abore 153 (FIG. 5) in the body it). The follower has a projecting ear 155which extends into an annular slot 157 at the rear of hammer Z2, andthus axial motion of the hammer will produce sliding movement of thefollower 15%, while free rotation of the hammer is unimpaired.

Referring particularly to FEGS. 5, 7 and 8, the follower 156 is providedwith a slotted rearward end 152; which receives a pawl 160 mounted on across pin hi2. This pawl is normally urged to a canted position,engaging one side of the bore within which the follower 15d slides asshown particularly in FIGS. 5 and 7. For this purpose, a ball 163engages the pawl is pressed by spring led against the back edge of thepawl, offset from the of rotation provided by pin 162..

Rearwardly of the follower and pawl there is a tapered annular camsurface 165 extending into a passage Hi7 of reduced cross-section whichin turn opens toward a valve body 163 mounted in bore 153 and threadedthereto at 169. The control rod 179 of a metering valve 172 extendsthrough this passage and centrally through the cam surface 165. Themetering valve head is normally seated upon an O-ring 174 or othersuitable seal, being held thereon by a light spring 175 which isreceived in valve sleeve 177 and held in place by a closed retainer cap179 threaded into the end of the body 163. Air under pressure issupplied to the interior of valve sleeve 177 through radially alignedpassages 178 formed in such sleeve and in the body 163, and thesepassages communicate with a cross passage is!) (FIG. 4) connected intothe direction control valve inlet passage 95 such that air is alwayssupplied through this passage regardless of the direction of rotationselected. These passages 178 are sealed oil at opposite sides by theO-ring seals 132 (FIG. 4) to retain the pressure air on the upstreamside or" metering valve 172 in non-operating condition. Downstream ofthe metering valve head and the O-ring seat 174 is a further passage385' including radially extending passages 187 which open into the maincontrol air supply passage 145, and this passage is confined (aroundbody 1:32) by one of the O-rings 182 and a further forwardly mounted{Hing 1&8 (FIG. 4).

Accordingly, for every axial movement of hammer 22, and thus of follower150, the pawl 16% will slide against the metering valve control rod 17%and will open the metering valve 172 to admit :air under pressurethrough the control passage 145 into the chamber 142 below the maincontrol piston 11%. As the follower and pawl continue to move, to theright as viewed in FIGS. 5, 7 and 8, the pawl will engage cam surface165 and further move ment of the follower and pawl will cause the pawlto be centered by the cam surface and the metering valve control rod 179will then line up with the internal opening 161 of the pawl, and spring175 will act to seat and close the starter valve. However, since anamount of air under pressure was thus admitted into the control passage145 and chamber 142, the main control piston 116 will be pumped upagainst spring 138 and subsequent closing of the starter valve will sealthe control passages and the control piston will remain essentially inits moved position. Subsequently actuations of the starter valve by pawl160, and further admissions of pressure air into the main controlpassages will cause the main control piston to rise further, in directrelation to the number of times that the hammer 22 strikes a blow. Withthe main valve 65 in the open position shown in FIG. 6, as the maincontrol piston 11% continues to rise its cam surface 149 willsubsequently engage the cam surfaces 135 on pawls 13a, and the pawlswill be urged apart against spring 132. Thus the control pin 185 will beforced upwardly between the pawls by reason of the combined effect ofair pressure and the pressure of spring 67 upon the main ball valve 65.This valve will seat and close off the supply passage d5 to terminatethe supply of motive fluid to the motor, and the tool will stop.

When the motor stops, the operator will thus know that the timedimpacting operation has been accomplished, and that a constant amount ofenergy, assuming that each blow struck by the hammer upon the anvilproduces essentially the same force, has bmn applied to tighten thefastener. When the operator releases trigger 15 it will be returned toits forward position by spring 87, and this will exhaust air from thechamber above servo piston 12%, with such air passing through the servooutlet passage Qtl, the chamber 85, and through an exhaust or ventingpassage 1% which is opened when the trigger is completely released, asshown in FIG. 5. At the same time, the area below the servo piston andabove the main control piston lid is also continuously vented throughvent passage 192. and the cross passages 1% to assure that no air istrapped within these parts to prevent completely free movement inresponse to actuation by either the air pressures thereon or therespective springs.

With the supply of air to the motor cut off, and thus no further supplyof air under pressure to passage 95 the pressure within this line willdrop considerably. A cross passage 20% is provided in the handle (FIG.10) between the motor supply passage 95 and the control passage 14-5 andthis cross passage is normally closed by a ball 2&2 seated upon anO-ring 2% due to the high pressure air in motor supply passage d5 whenthe tool is operating. However, when this pressure drops the pressureair within passage lid-5 and beneath the main control piston 11d willforce the ball 262 to unseat, and the spring 133 will then return thecontrol piston 119 to the bottom of the counterbore 112, the positionshown in FIG. 5. The tool is then prepared for a further operation,which can be initiated H by depression of the trigger by the operator tostart the timed impacting cycle again.

By controlling the size of the orifice defined by the metering valve 172when it is opened, it is possible to meter a predetermined amount ofpressure fluid into the control passage for each impact or blowdelivered by hammer 22. Thi may be accomplished conveniently bythreading the body 168 to adjust its axial position, thus controllingthe spacing between rod 17% and pawl lied, and changing the amount ofopening of valve 172 for each stroke of pawl 15%). Accordingly, for eachtightening operation the hammer will deliver a predetermined number ofimpacts, which number is definite and constant for each cycle, and thenstop, and an essentially constant or predetermined amount of energy isdelivered to tighten the fastener in each cycle or" operation or thetool.

As mentioned at the beginning of the specification, the basic objectiveis to utilize a substantially constant energy for the tightening of thefasteners. The apparatus above described provides such constant energytightening by controlling the number of impacts which the rotaryimpacting tool delivers to the fastener. It is also possible to time theoperation of the impacting tool from the first impacting blow and thusto permit the tool to strike impacting blows for a predetermined lengthof time, the number of impacts delivered thus being dependent upon thelapse of time from the first blow,

FIG. 11 shows a modified form of starter valve, and in this figure likereference numerals have been applied to parts which are identical tothose shown in FIGS. l-lt). It will be noted that even the starter valvehousing 152 is of the same construction, and all parts not shown in FIG.11 are of the same construction as previously described. Thus, theoperation of the trigger will result in air under pressure beingsupplied through passage 5 to the radial passages 178 in the housing152, and these passages are normally closed by a modified starter valve21th which is slidably received within the housing in place of thesleeve 177. The forward end of this valve is of reduced diameter, asshown, and seats against an O-ring threaded into the handle 12 of thetool.

215 normally closing against passage of pressure fluid into the passage187. The starter valve also includesa rod like portion 217 which extendsforwardly across passages 187 and a forward guiding and control rod 218which is adapted (in the same manner as control rod 1'70) to be engagedby the pawl 160 upon the first axial movement of the hammer. Spring 219normally urges the starter valve 210 to its closed position as shown,thus closing off the passages 178,

Upon movement of the hammer at the first impact the pawl 160 will engagecontrol rod 218 and force starter valve 210 rearwardly against spring219. Thus,

. the passages 17% will be uncovered and air under pressure will enterthe central portion of the housing 152 around the reduced diameterportion 210, and this pressure air will act to hold the starter valveopen against spring 219, maintaining a passage for pressure air intopassage 187 and thence into passage 145. Within this passage, prior tothe opening thereof beneath the control piston 119, there is a needlevalve 220 which is adjustably mounted within a threaded sleeve 222. Thissleeve in turn is The needle valve 220 can be adjusted to control theorifice through which the pressure air must pass to the control piston110, and thus the rate of fiow through passage 145 can be established insuch a way that the time required for the control piston to reach itsreleasing position, shown in FIG. 9, will be a predetermined intervalfollowingthe first impact, and of-course this interval will be definiteand constant for each cycle of operation of the tool.

When the operation of the impacting tool is automatically terminated bythe apparatus, the trigger will be released as previously explained tovent passage 145, and the starter valve will be reset by the spring.

FIG..12 shows a modified arrangement for providing constant energy froma rotary impacting tool operated by an electric motor. Essentially thesame theory of operation is employed, and the apparatus shown willfollow the same mode of operation as previously described. The impactingtool per se is of the same general construction as previously described,and includes a rotatable hammer 240 driven from a spindle 242 which inturn is driven by reduction gearing 243 from a reversible electric motor245. The hammer 249 carries a follower 247 which operates to close anormally open switch 250 each time the follower is carried toward therear of the tool by the hammer.

The trigger 252 operates a further normally open switch 254 which willclose upon depression of the trigger. The direction of rotation of themotor may be controlled by conventional means, which maybe operated bymovement of a reversing cap 255 on the rear of the tool. The electricleads from the motor 245 and switches 250 and 254 are passed from thehandle of the tool through a conventional cable, a five conductor cablebeing required in this instance, to a control arrangement which may beconveniently located in a control box 257 shown in dotted lines in FIG.12. Electrical power may be supplied from any convenient source, forexample 110 volt A.C., through the leads L1 and L2. It will be notedthat the lead L2 is connected directly to the conductor. or line 258which leads to motor 245 and to one contact of the trigger switch 254.

When the trigger 252 is depressed and switch 254 is closed, this willcomplete a circuit through line 258 and a further line 259 through thecoil of a double-acting A.C. relay 260, and this relay will actuate toopen its normally closed contacts 262 and to close the normally opencontacts 264. This completes a circuit through line 265 to supply powerto motor 245, and the impacting tool will operate.

When the hammer strikes its first impacting blow the follower 247 willclose switch 256) and complete a DC. circuit through lines 267 and 268which are connected across a full wave rectifier network 270 supplyingDC and receiving AC. power from the lines L1 and L2. Be-

tween line 268 and rectifier network 270 there is. con nected a seriescircuit including a variable resistor 272 and a capacitor 275. Thus,each time switch 250 is closed the capacitor 275 will be chargedsomewhat, depending upon the current fiow through the resistor 272.

When the capacitor 275 is charged to its full capacity, the potentialdifierence across it will be sufficient to fire the cold cathodethyratron 278, which has its cathode connected to rectifier network 270and capacitor 275, and its grid connected to a point between capacitor275 and variable resistor 272. The plate circuit of the thyratronincludes a DC. relay 280. having normally closed contacts 282 which arein series with the contacts 264 of relay 260. Thus, energizing relay 280will open the motor circuit and stop the tool. Then, when the trigger isreleased switch 264 will open and relay 260 will be deenergized, openingcontacts 264 and 284 to extinguish the thyratron 278, and completing adischarging circuit through the back contacts 262 to dissipate anyresidual charge on the capacitor 27 5.

It is also possible to provide a timing circuit in which the lapsed timefrom the first impact blow determines the amount of energy expended bythe tool upon the fastener, or in other words, an electrical equivalentof the modification shown in FIG. 11. Such a modified circuit embodiesthe same construction shown in FIG. 12, with the addition of aconventional holding circuit connected by the lines 267 and 268 suchthat once the contacts 250 have been closed, the current flow throughthe resistor capacitor network is maintained, and the physical constantsof this network thus will determine the lapse of time required beforethe grid potential of the thyratron is sufficiently positive withrespect to its cathode to fire the thyratron and shut off the electricalenergy supply to the tool motor in the same manner as previouslydescribed.

While the forms of apparatus herein described constitute preferredembodiments of the invention, it is to be understood that the inventionis not limited to these precise forms of apparatus, and that changes maybe made therein Without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

1. A rotary impact device comprising a rotary motor, a rotary hammerconnected for driving thereof by said motor, an anvil mounted for rotarymovement in driving engagement with said hammer, parts acting on saidhammer and responsive to deceleration of said hammer to disengage saidhammer from said anvil and to provide for acceleration of said hammerproducing a subsequent blow on said anvil tending t rotate said anvil,means 'connectedto supply power to said motor including a controlarranged to govern the supply of power, and cycle control meansconnected to said power control operative upon initiation of thestriking action of said hammer upon said anvil for terminating the powersupply to said motor in response to application of a predeterminedamount of energy to said anvil by said hammer.

2. A rotary impact tool comprising a rotary motor, a rotary hammerconnected for driving thereof by said motor, an anvil mounted forrotarymovement in driving engagement with said hammer, parts acting onsaid hammer and responsive to deceleration of said hammer to disengagesaid hammer from said anvil and to provide for acceleration of saidhammer producing a subsequent blow on said anvil tending to rotate saidanvil, means connected to supply power to said motor including a controlarranged to govern the supply of power, and cycle control meansconnected to said power control operative upon imitation of the strikingaction of said hammer upon said anvil and responsive to a definite andconstant lapse of time for each cycle of operation of the tool followingthe first actuation of saidhammer parts to terminate the power supply tosaid motor. I

3. A rotary impact tool comprising a rotary motor, a rotary hammerconnected for driving thereof by said motor, an anvil mounted for rotarymovement in driving engagement with said hammer, parts acting on saidhammer and responsive to deceleration of said hammer to disengage saidhammer from said anvil and to provide for acceleration of said hammerproducing a subsequent blow on said anvil tending to rotate said anvil,means connected to supply power to said motor including a controlarranged to govern the supply of power, cycle control means connected tosaid power control and responsive to a definite and constant number ofactuations of said hammer parts during each cycle of operation of thetool for terminating the power supply to said motor, and power supplymeans including a trigger controlling the supply of power to said motorand connected to maintain at all times a control over said power supplycapable of terminating the actuation or said cycle control means priorto the full number of actuations of said hammer parts for which it isset.

4 A rotary impact tool comprising a rotary motor, a rotary hammerconnected for driving thereof by said motor, an anvil mounted for rotarymovement when in driving engagement with said hammer, parts on saidhammer normally engaged with said anvil and responsive -to decelerationof said hammer to disengage temporarily from said anvil to provide foracceleration of said hammer producing a subsequent blow on said anviltending to rotate said anvil, means connected to supply power to saidmotor including a control arranged to govern the supply of power, cyclecontrol means connected to said power control and responsive to adefinite and constant number of actuations of said hammer parts duringeach cycle of operation of said tool for terminating the power supply tosaid motor, and means operative on said cycle control means to vary thenumber of actuations required for response thereof.

5. A rotary impact tool comprising a rotary motor, a rotary hammerconnected for driving thereof by said motor, an anvil mounted for rotarymovement in driving engagement with said hammer, parts on said hammernormally engaged with said anvil and responsive t deceleration or" saidhammer to disengage temporarily from said anvil providing foracceleration of said hammer to produce a subsequent blow on said anviltending to rotate said anvil, means connected to supply power to saidmotor including a control arranged to govern the supply of power,automatic cycle. control means connected to said power control andresponsive to a definite and constant number of actuations of saidhammer parts during each cycle of operation of the tool for terminatingthe power supply to said motor, a manually actuated power controlconnected into said power supply means to control the supply of power tosaid motor prior to said automatic power control means, and a resetconnection in said manual power control requiring shut otl" of the powersupply by said manual power control before another automatic cycle canbe initiated.

6. In a rotary impact tool having an anvil and a motor driving a rotaryhammer having parts arranged to deliver successive impacts to said anviltending to rotate the same, the combination of a manually operablecontrol trigger, means connected to control the supply of power to themotor and operable to initiate the power supply in response to actuationof said trigger, cycle control means responsive to a definite andconstant lapse of time following the first impact delivered by saidhammer parts during each cycle of operation of the tool and connected tosaid power control means to cause termination of .the motor power supplyat such response to lapse of time, and means forming a reset connectionbetween said cycle control means and said trigger requiring release ofsaid trigger after automatic termination of the power supply to initiatea further operating cycle.

7. In a portable rotary impact tool having a housing including a handleand an anvil and a motor driving a rotary hammer having parts arrangedto deliver successive impacts to said anvil tending to rotate the same,the combination of a manually operable control trigger adjacent saidhandle, means in said housing connected to control the supply or powerto said motor and operable to initiate the power supply in response toactuation of said trigger, cycle control means also mounted in saidhousing and responsive to a definite and constant lapse of timefiollowing the first impact delivered by said hammer parts during eachcycle of operation of the tool and connected to aid power control meansto cause termination of the motor power supply at such response to lapseof time, and means forming a reset connection between said cycle controlmeans and said trigger requiring release of said trigger after automatictermination of the power supply to initiate a further operating cycle.

8. In a portable rotary impact tool having a housing including agripping handle, an anvil, a motor in said housing, a rotary hammerdriven by said motor and having parts arranged to deliver successiveimpacts to said anvil tending to rotate the same, a manually operablecontrol trigger carried in said handle, servo system means connected tocontrol the supply of power to the motor and operable to initiate thepower supply in response to actuation of said trigger, cycle controlmeans mounted in said housing including parts responisve to a definiteand constant number of impacts following the first impact delivered bysaid hammer parts during each cycle of operation of the tool andconnected to said power control means to cause termination of the motorpower supply, and means for adiusting said cycle control means to varythe number or" impacts which cause such response thereof.

9. In a portable rotary impact tool having a housing including agripping handle, an anvil, a motor in said housing, a rotary hammerdriven by said motor and having parts arranged to deliver successiveimpacts to said anvil tending to rotate the same, a manually operablecontrol trigger carried in said handle, servo system means connected tocontrol the supply of power to the motor and operable to initiate thepower supply in response to actuation of said trigger, cycle controlmeans mounted in said housing including parts responsive to a definiteand constant number of impacts following the first impact delivered bysaid hammer parts during each cycle of operation of the tool andconnected to said power control means to cause termination of the motorpower supply, means for adjusting said cycle control means to vary thenumber of impacts which cause such response thereof, and means forming areset connection between said cycle control means and said triggerrequiring release of said trigger after automatic termination of thepower supply to initiate a further operating cycle.

Jill. A rotary impact t-ool having an anvil adapted for connection torotate fasteners and the like, a hammer having parts arranged to deliverimpacts to said anvil, a motor having a driving connection to saidhammer, means connected to control the power supply to said motor andoperative at rest to prevent supply of power to said motor, a triggeroperative to cause said power supply control means to actuate saidmotor, and cycle control means operable so long as said trigger isactuated and responsive to a definite and constant number of impactsduring each cycle of operation of the tool to override the action ofsaid trigger on said power supply control means and to cause terminationof the power supply to said motor.

11. A rotary impact tool having an anvil adapted for connection torotate fasteners and the like, a hammer having parts arranged to deliverimpacts to said anvil, a pressure fluid rotary motor having a drivingconnection to said hammer, a power connection adapted for coupling to asource of pressure fluid, a normally closed servocontrolled main valveconnected in series between said power connection and said motor, aservo-operator for 'said main valve including release mechanismtherefor, a normally closed servo-valve connected to control supply .ofpressure fluid from said source to said operator, a trigger operable inresponse to continued actuation thereof to open said servo-valve toefifect operation of said servo-operator and opening of said main valve,an impact responsive device connected to supply a predetermined quantityof pressure fluid to said release mechanism in opposition to saidservo-valve for each impact delivered by said hammer, said releasemechanism being effective to release said main valve and to terminatethe motor power supply in response to a predetermined total quantity ofpressure fluid supplied from said impact responsive device, and resetapparatus on said servo-operator requiring release of said trigger foreflective subsequent action of said trigger and said servo-Valve on saidservo-operator.

12. A rotary impact tool having an anvil adapted for connection torotate fasteners and the like, a hammer having parts arranged to deliverimpacts to said anvil, a pressure fluid rotary motor having a drivingconnection to said hammer, a power connection adapted for coupling to asource of pressure fluid, a normally closed servocontrolled main valveconnected in series between said power connection and said motor, aservo-operator for said main valve including release mechanism therefor,a normally closed servo-valve connected to control supply 'of pressurefluid from said source to said operator, a trigger operable in responseto continued actuation thereof to open said servo-valve to eflectoperation of said servo-operator and opening of said main valve, animpact responsive device connected to supply pressure fl'uid to saidrelease mechanism in opposition to said servo-valve for a predeterminedlength of time, following the first impact delivered by said hammer,said release mechanism being effective to release said main valve and toterminate the motor power supply in response to a predetermined totalquantity of pressure fluid supplied from said impact responsive device,and reset apparatus on said servo-operator requiring release of saidtrigger for eifective subsequent action of said trigger and saidservovalve on said servo-operator..

-13. A rotary impact tool having an anvil adapted for connection torotate fasteners and the like, a hammer having parts arranged to deliverimpacts to said anvil, an electric rotary drive motor having a drivingconnection to said hammer, a power supply connection to a source ofelectrical power, a main control relay having normally open contactsconnected between said power connection and said motor, a servo relayhaving normally closed contacts also connected between said powerconnection and said motor, a trigger operative to energize said mainrelay for supplying power to said motor, a charge accumulating circuitconnected to said servo relay and responsive to a predetermined quantityof charge to energize said servo-relay and interrupt said power supply,means responsive to each impact to apply a predetermined electricalcharge to said accumulator circuit, and reset circuit means responsiveto release of said trigger to reset said charge accumulator circuit.

14. A rotary impact tool having an anvil adapted for connection torotate fasteners and the like, a hammer having parts arranged to deliverimpacts to said anvil, an electric rotary drive motor having a drivingconnection to said hammer,- a power supply connection to a source ofelectrical power, a main control relay having normally open contactsconnected between said power connection and said motor, a servo-relayhaving normally closed contacts also connected between said powerconnection and said motor, a trigger operative to energize said mainrelay for supplying power to said motor, a charge accumulating circuitconnected to said servo-relay and responsive to a predetermined quantityof charge to energize said servo-relay and interrupt said power supply,mean responsive to the first impact delivered by said hammer to apply apredetermined electrical charge at a predetermined rate to saidaccumulator circuit, and reset circuit'means responsive to release ofsaid trigger to reset said charge accumulator circuit;

References Qited by the Examiner Donowick 81--52.3

DON A. WAI-TE, Primary Examiner.

MORRIS M. FRITZ, Examiner,

1. A ROTARY IMPACT DEVICE COMPRISING A ROTARY MOTOR, A ROTARY HAMMERCONNECTED FOR DRIVING THEREOF BY SAID MOTOR, AN ANVIL MOUNTED FOR ROTARYMOVEMENT IN DRIVING ENGAGEMENT WITH SAID HAMMER, PARTS ACTING ON SAIDHAMMER AND RESPONSIVE TO DECELERATION OF SAID HAMMER TO DISENGAGE SAIDHAMMER FROM SAID ANVILK AND TO PROVIDE FOR ACCELERATION OF SAID HAMMERPRODUCING A SUBSEQUENT BLOW ON SAID ANVIL TENDING TO ROTATE SAID ANVIL,MEANS CONNECTED TO SUPPLY POWER TO SAID MOTOR INCLUDING A CONTROLARRANGED TO GOVERN THE SUPPLY OF POWER, AND CYCLE CONTROL MEANSCONNECTED TO SAID POWER CONTROL OPERATIVE UPON INITIATION OF THESTRIKING ACTION OF SAID HAMMER UPON SAID ANVIL FOR TERMINATING THE POWERSUPPLY TO SAID MOTOR IN RESPONSE TO APPLICATION OF A PREDETERMINEDAMOUNT OF ENERGY TO SAID ANVIL BY SAID HAMMER.